1. Field of the Invention
The present invention relates to a method of setting a peak-timer when a storage battery is to be rapidly charged.
2. Description of the Related Art
It is well known to use secondary batteries, especially Ni--Cd types, in various fields as power sources for cordless telephones, video recorders and other home electric appliances. The Ni--Cd type of storage battery is frequently used, and during its use thereof, charging must be performed often, usually by what is commonly referred to as a "rapid charge" or "quick charge" method. In general, the rapid charging is carried out for about 1-2 hours at a charging rate in the range of 0.5.degree. C.-1.5.degree. C., where C represents a current value equal to the normal capacity of the battery in amp-hours. However, charging rates vary with different types of batteries.
Rapid charging subjects the storage battery to severe treatment, and therefore it is necessary to control rapid charging so as to prevent overcharging Regarding systems for detecting rapid charging, a -.DELTA.V system, a voltage detecting system, etc. have been put into practical use. Further, in order to prevent the battery from damage resulting from rapid charging, at least one of a total-timer, a temperature protective device and a voltage protection device is provided and actuated. Here, the total-timer refers to a device that regulates a period of time from a starting time point to an ending time point of the rapid charging, so that the charging operation occurs only for a predetermined period of time. Typically, a total-timer is used together with a peak-timer. The peak-timer starts its charging operation with the detection of a peak value of a charging voltage, and the charging operation is then stopped after a predetermined elapsed time after detection of the peak voltage value by either the total-timer or the peak-timer, whichever expires earlier.
When a total-timer is conventionally operated in a rapid charging operation, the setting and starting of the operation of the peak-timer are carried out without any time-relationship established between the peak-timer and the total-timer. Namely, the setting and starting operations of the total-timer are performed first, and when the peak value of the charging voltage is detected after a lapse of time from the start of rapid charging, the setting and starting operations of the peak-timer are then performed. Accordingly, it is typically necessary to treat the setting and starting operations of the total-timer and those of the peak-timer separately from each other, which can become burdensome to an operator.